Recently I was given a couple .22 pistols. One was a H&R "Young American" 7 shot, the other was a H&A "XL Double action". I have read that these guns were Rimfire Black Powder. Both could be shooters, I don't want to damage either gun, they are very poor appearance, but after cleaning dry fire okay.
Woul 22 short be usable, or should I find or make 22BP.

The 22 was originally a black powder cartridge, I think that is what they mean by Rimfire Black Powder.
That is why there is so much extra space in a 22 case from going to modern powder.
I sure wouldn't run stingers or minimags through them, but then I only use standard velocity
in a handgun as I find them more accurate.
Anyone else help us out on this?
best wishes

Never dry fire. 22 LR. With no case rim to pinch the hammer will damage the Chambers.
Look up the year the guns were made and see what ammo was available. I would guess CB rounds might be ok if more powerful ones are not.

Never dry fire. 22 LR. With no case rim to pinch the hammer will damage the Chambers.

That's not exactly completely true. I have a Hi Standard Sentinel Model 101 with notches cut into the cylinder for the fireing pin to rest in. So while most firearms don't have that, some do. It's worth looking.

Here's an article about Black powder 22's, looks like they were about 1100 or so fps.

Looks like the 1100 FPS value was achieved in a rifle with a 40 GN projectile. Match grade .22 LR ammo with the same weight projectile achieves velocities in the 1050 to 1080 FPS range with a 28 inch barrel. CCI SV LR may work just fine.

Stay away from stingers or HV ammo. Try the drop in chamber test with a LR.

A 22 LR is a no go in both guns, on the H&R it protrudes almost 1/4" from the cylinder,r on the H&A protrude about .02". My question is regarding 22 shorts. The H&R is so small and lightly made, a cap gun looks heavy duty compared to it.